Ultrasensitive Raman measurements in single living cells are possible through exploiting the effect of surface-enhanced Raman scattering (SERS). Colloidal gold particles (60 nm in size) that are deposited inside cells as “SERS-active nanostructures” result in strongly enhanced Raman signals of the native chemical constituents of the cells. Particularly strong field enhancement can be observed when gold colloidal particles form colloidal clusters. The strongly enhanced Raman signals allow Raman measurements of a single cell in the 400–1800 cm ⁻¹ range with 1-μm lateral resolution in relatively short collection times (1 second for one mapping point) using 3–5 mW near-infrared excitation. SERS mapping over a cell monolayer with 1-μm lateral resolution shows different Raman spectra at almost all places, reflecting the very inhomogeneous chemical constitution of the cells. Colloidal gold supported Raman spectroscopy in living cells provides a tool for sensitive and structurally selective detection of native chemicals inside a cell, such as DNA and phenylalanine, and for monitoring their intracellular distributions. This might open up exciting opportunities for cell biology and biomedical studies.

Carbon nanodots are a new and intriguing class of fluorescent carbon nanomaterials and are considered a promising low cost, nontoxic alternative to traditional inorganic quantum dots in applications such as bioimaging, solar cells, photocatalysis, sensors and others. Despite the abundant available literature, a clear formation mechanism for carbon nanodots prepared hydrothermally from biomass precursors along with the origins of the light emission are still under debate. In this paper, we investigate the relationships between the chemical structure and optical properties of carbon nanodots prepared by the hydrothermal treatment of glucose. Our major finding is that the widely reported excitation-dependent emission originates from solvents used to suspend the as-prepared carbon nanodots, while emission from dry samples shows no excitation-dependence. Another important highlight is that the hydrothermal conversion of biomass-derivatives under subcritical conditions leads to a heterogeneous mixture of amorphous-like nanoparticles, carbon onion-type and crystalline carbons composed of at least three different phases. The potential chemical reaction pathways involved in the formation of these hydrothermal carbon products along with a comprehensive structural and optical characterization of these systems is also provided.

The hydrothermal synthesis of nitrogen-doped monolithic carbon aerogels derived from sustainable precursors (i.e.D-glucose and ovalbumin) is presented. The protein acts as nitrogen donor and surface stabilizing agent in this saccharide hydrothermal carbonization, to generate high surface area aerogels (>240 m²g⁻¹) composed of functional continuous large diameter mesopores with excellent hierarchical transport architecture. Post-carbonization treatment controls surface chemistry (e.g. C or N condensation), facilitating tuneable physicochemical properties on a unique continuous 3D carbonaceous pore structure. This highly flexible synthesis lays the basis for the development of a new generation of sustainable (heteroatom-doped) porous carbon aerogels suitable for a range of high value applications.

A-Axis-oriented undoped n-BaSi2epitaxialfilms were grown on Si(111) substrates by molecular beam epitaxy, and the crystalline quality and grainboundaries were investigated by means of reflection high-energy electron diffraction, X-ray diffraction, and transmissionelectronmicroscopy (TEM). The grain size of the BaSi2films was estimated to be approximately 0.1–0.3 μm, and straight grainboundaries (GBs) were observed in the plan-view TEM images. Dark-field TEM images under a two-beam diffraction condition showed that these GBs consist mostly of BaSi2 {011} planes. The diffusion length of minority carriers in n-BaSi2 was found to be approximately 10 μm by an electron-beam-induced current technique